Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare read-only, idempotent, and non-destructive behavior. The description goes beyond these by adding 'deterministic,' 'pure compute, no network,' and 'paid per call,' which provide useful operational context. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is exceptionally concise: three short clauses that immediately convey purpose, algorithms, offline behavior, and cost. Every sentence earns its place and there is no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple pure-compute tool with rich annotations and fully documented parameters, the description is nearly complete. The only minor gap is that it does not explicitly state the return format (e.g., hex-encoded digest), and there is no output schema to compensate.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3. The description restates the algorithm options and default already present in the schema but adds no new parameter-level details such as encoding, formatting, or edge cases.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly identifies the action—hashing a text string—and the supported algorithms. It is specific enough to distinguish paid_hash from the sibling paid_* tools, none of which are hash utilities.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies when to use this tool: whenever a deterministic hash of a text string is needed. It does not explicitly state alternatives or conditions to avoid this tool, though 'pure compute, no network' gives some context about its scope.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.